1.) The criminal must be someone mentioned in the early part of the story, but must not be anyone whose thoughts the readers has been allowed to follow.

To start the list, Knox establishes the rules of the game. Mysteries hold so much allure because they are the most interactive. Remember those old choose-your-own-adventure stories? Well-written mysteries allow the reader to step into the story and try their hand at solving the riddle, bring the reader into the story far more effectively than making a choice and turning to a specific page. Interestingly, Knox also reveals the aspect of mysteries that separates it from the likes of thriller where the criminal is not an option regarding Point of View.

2.) All supernatural or preternatural agencies are ruled out as a matter of course.

Here, Knox makes a distinction regarding the mystery genre as an autonomous category. Fantasy and like get their own set of rules, but there are plenty of authors who are successfully blending the genres, like Jim Butcher with his Dresden Files series. This also speaks to the idea that the detective must be the one to solve the mystery.

3.) Not more than one secret room or passage is allowable.

Alas, Clue was before Knox’s time.

4.) No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.

This, I think, is something that has crept into the genre some, especially on the TV-side of things. Shows like CSI, CSI: New York, and CSI: Albuquerque all push the forensic envelop, but I think the point Knox is trying to make here is connected to the one from the first commandment: Let the reader stay in the game. To delve too deeply into the science of the crime will alienate most readers who aren’t, in fact, scientists.

5.) No Chinaman must figure in the story.

While I’d love the idea of a priest to be wildly racist and incredibly uncouth (not that there weren’t/aren’t any), Knox is really making a larger point on avoiding cliche. To rely on racial stereotypes was a sure sign that the story was weak. So avoid Chinamen, Rednecks, Vatos, and the like.

6.) No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.

This commandment is related to the second one in that the mystery needs to be solved fairly, with the detective finding the solution with a logical progression through the clues. It’s an integral part of the writer-reader pact.

7.) The detective must not himself commit the crime.

The detective is the hero of the story, and the character the reader most often identifies with. This is particularly true of the Cozy. So, to make the detective the criminal would be a betrayal of the reader. It’d be breaking the established rules of the game. Besides, twists like that are better served for the thriller genre.

8.) The detective must not light on any clues which are not instantly produced for the inspection of the reader.

This rule speaks to keeping the story an authentic, traditional mystery. The clues, as they appear, must be available to the reader or the detective has an unfair advantage. To keep the clues from the reader makes it an unsolvable mystery and thus the story loses its true appeal. What makes mystery writing so interesting, and difficult, is to present all the clues to the reader all the clues and making assembling them correctly the real task.

9.) The stupid friend of the detective, the Watson, must not conceal any thoughts which pass through his mind; his intelligence must be slightly, below that of the average reader.

Poor Watson. My students were insulting him in class today, but his character trope is an important part of the mystery. They are useful for the detective to serve as a sounding board–to have someone to explain everything to. It’s this character that can ask the obvious questions the reader may be wondering, and reading the Watson’s thought processes can also helper to the reader.

10.) Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.

Here is another rule that forbids plot machinations. Avoid deus ex machinas in mysteries because they cheapen the product. Everything in the story needs to be set up and presented, not twisted into the light at the end. The criminal can in fact have a twin, or be a master of disguise, but those elements need to be weighted early in the story.

So here they are, the 10 Commandments of Detective Fiction. What do you, my dear Watson reader, make of them?

Published by David Fernandez

Out there, I'm a husband, father, son, brother, friend, teacher, and coach. In here, sitting at my desk, I'm an aspiring fiction writer who dabbles in sports journalism. Check out my work at ByDLFernandez.com, or follow me on Twitter @ByDLFernandez.
View all posts by David Fernandez

Post navigation

I like these rules, and agree with them pretty much all the way. I wonder if there is a rule for the number of red herrings allowed in a mystery? 🙂 Thanks for sharing these, David. They make perfect sense to me. As for writing Fantasy, Urban or otherwise, anyone who thinks there are no rules involved in building those worlds is in for a big surprise. The first thing that has to be done is to figure them out, and then stick to them. I hate when I’ve been following something with clearly defined characteristics of a species, for example, and then they are changed, mid-game, because they aren’t convenient any more.

Hi Marcia! thanks! Yeah, I’m with you on hating when a story changes the rules on you mid-read. It’s all about staying consistent to what you establish. The best part about writing rules is, if you have a good enough reason, you can break them!

Content

Follow me on Twitter

Out there, I'm a husband, father, son, brother, friend, teacher, and coach. In here, sitting at my desk, I'm an aspiring fiction writer who dabbles in sports journalism. Check out my work at ByDLFernandez.com, or follow me on Twitter @ByDLFernandez.